SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17fc5a1ab009638a606a23a83643068e920ad5dafbf1e7e3336478492aa48359' 
  AND token = 'WFgevRxPQ6XXti2Kh+dMo/1YsAFOzc7eFsF2j+fy4SQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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