SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11e21994a2152d1d243cf8439953a6b281415786e3f7d8a7a584e661d719739d' 
  AND token = '0inGciilUYr+Rqte+vkoqhDYwwfaXdt6Gtl/BUFVob4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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