SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38667024e6c465131d6eed5b7fc41f0468b202e0a4b057275d2b26911f4d1b59' 
  AND token = 'DXXnCqXpWPn4D01GZGgnjrEn56xkCdVAON4Gsuw4XNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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