SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2fcf14c4f991c196a70c3ebcf5ac38b8e40ed94c031d4fc65e258195edac5d' 
  AND token = 'MMtH6zFRbAfCxH8pC1vwMrezj6LVWH/EJEux1y4SHVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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