SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5000fddbee09c529bb7d7ad67ef51549807b8e8bf39dbb7fd57fe389b0831432' 
  AND token = 'OV392YZxPjdL7pjfO9NAP3a/o+q1qDzB61H22rcr/UM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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