SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd5199a86e868debfe65df91fae2f982086c367f9a0b5ed319a80d73b4cf0651' 
  AND token = 'pJtL/RU4ArMzl5GB9pCwzgn2mWdZSSgSF7s2DK/3WYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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