SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37351879f97c1f183d6edd2155a4e577bed1583116415c0e1bb269314cdf9822' 
  AND token = '6TeuaFbq0V7uulVVV0qTKjJAndMfihWNpfqrKYvlmdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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