SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3519931af6b792f3116722f9bebd0618d51808e557a57d3cef77242ae0cb3a7' 
  AND token = 'W+jyCLOfxTVPgo47J8MFzyRQEz0e44XhmDMZBd2MUg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}