SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4959029565e6838c86b19d105fe4ab87b0d9355fcec7892bbabf2a9f394fdca3' 
  AND token = 'ePRI7Ax+/9dLEsYBWKP5vXQa3iHEiEOiwFZZ/EV8DGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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