SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a86563c5242864f0326a210c49e8a655c2e2a40c418b4d5a26cff67c139c0c54' 
  AND token = 'XWMkL3/z/tblQLFePBqSCntJuphNdvXLbDBys36izrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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