SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7d4defc276293060f4756bd1c4207ffeefdb3bfdf1c67519a2abab925214a19' 
  AND token = 'Yt9rLdEris9aQKhENkIO8s/2KN4rHSeJILjfrlFIm0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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