SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e10f162293d62fd2bf4655168d1443c21ebfbcac10bb053d86adafb9b5ea3e98' 
  AND token = '5JDXYOhbW+zmFongc4g1XmnSrE55MXkcwslI3BXCnTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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