SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc8d43a48adbad1b6eb89bdfa205c72b9f4826fdfb1afcaef832fe050fbee57b' 
  AND token = 'E3VthnJE8pDxKisi1h7KWkYADujkdx7Gkl4LqbEHxLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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