SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31d0ba04d4bdcb9499d8983897ea0e19406d4350fb6957ba46d5f9725f85024c' 
  AND token = 'SISHrauG3oqPSnv8IAGnREAMw8SAMCIPOO8qUMSRyZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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