SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6c316dd675844d675af67c47b381e8b6cf4c6c19014375930d71b53b3f39075' 
  AND token = 'oM8Mx0DNr5eJg2SdexwZZvN2SBA+Gaq7lMWAUKP9/3g=' 
  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"
    }
  }
}