SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5851d454e92363e4c87f3c22fe7b7733deaf911a60c9c52510f885c3d0f6e470' 
  AND token = 'RQ5K+P+N+iJM0MZbqqioCZNHSPwvdpBcNGnVpFsj4F8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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