SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9de91e1af3b88ff1dc9524194709a2c998a412b2083d63e59046c58ac63fcc1' 
  AND token = 'O19r02xK2ygG/EWZVUWqhwLCZASnYdRkmDeez+HakIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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