SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc306ace0866aeb1839f2ac6f6d726a136d1c3a91ebd68614e362ea811de0311' 
  AND token = 'frN+j+S14h9ffN0YK6/sQQhncmIBeVDF89ZgEeU06WI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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