SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff739ff5502463632b104a0aa4181c3d8b29752a25b91889d3a41e3826fc6e14' 
  AND token = 'cv1Kya3e/ozMSZmUWMj4p+ZVjL6hBbtXKqvG5TZxxno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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