SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbf87c9afdc323f4563d813192395927f4f5aa8c340333ed7aeba29288ee62f5' 
  AND token = 'MJXWYLc48QhJF/sIKeCWEQfAhXvnnQqoM8RJZ4q56BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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