SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c85937ccfdc417cebc456d4d774e4e07b6f6a7bd25379188ad30d2e4476b60bf' 
  AND token = 'KIFCi2W/eSFEJdsalFvautjl7yrvKvqwkbvb0OQy5XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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