SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53fd359e19b58a8351912859d1a8719b8739ad05c443d697b8a695b26c7c8f3d' 
  AND token = 'qMA38Xtx2aWZuIaw3cUNMFCEDsrzCTyr3trNZyoQ5YA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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