SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c60c26cb6ff0875a52b3e44788692f794dd07c35d944d1a33378ffd1708cfe4' 
  AND token = 'm1TgT8DiGL+NnG4qWaiv4D0CtUJWhAx6242vOHlR3Ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}