SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '339d39a99080779cc01eeced260430f47b7efdedd6fc8a9902426748913bc265' 
  AND token = 'BgP6hPh7vbIWgFXSe2X+wOEOjyJvzRyTgrN/D5Wd/RY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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