SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b2f10399c47ce489813c141302297f05f24778db010384b2ac225f7443e31d1' 
  AND token = '9sCSFT8OUpi0ZnXfZDWnAbZYb6Y+BgKCsjhSlNbSf/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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