SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a752866ccf0faeb277dbd340071eddfba321c833684546a4920526a7e65e8e8a' 
  AND token = 'LbSGDWUp43T2PGZbHPpiT5kXqnRmGmaBAL6aWWQb7HA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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