SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84be14855b06698255defdf0bf599f7ccf9b0400c000c8defa887561e6e25953' 
  AND token = 'yp3pi+UkqB9uHPhupl1w7Xp2hGVrsGdS/KT1MZqyVEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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