SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bece64e23e73f864e47b6f76ae76cc4a568fc26655ee0a7b41913b1971a09f91' 
  AND token = '4WOYb7YuHmdcHNm3ssifwYVNknobPtgiSOhavrfZ76g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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