SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccead3a18910660d52c92c3ccfada04faa3de742ef1464c58e2d83964a8daff1' 
  AND token = 'E2+fhHYdCgogbal370RzwuyTiQSE17OQjbEFqyz6Tdk=' 
  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"
    }
  }
}