SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfbcc4995e2bd371392f1670dd035af1c95bfbaa8b5a7d8800d7068d51f92afe' 
  AND token = 'TV4HfvYdplcJTcaMT9rzMaC+/k3/pMoWLFfQIpl8lGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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