SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '983e770ad801df021b6a886b080c7b185376cde894e00871abdd6f4f7e72f48a' 
  AND token = '1x/Y7dPku5yTUvWd+CpZ0M0LmSxVko+IDPVzuSCx7yI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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