SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c3ca54eaf418467c86f2d3856ecb65d285dc32cf739ea04e755778a075b8707' 
  AND token = 'u/RG6q2L4AhHwFBvMEaQTl5FrpCUUw7EqaorjHV7VIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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