SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d02ea95fa73310e04ef96eddbc662513a3ef27624359974a28a67a671a748c1' 
  AND token = 'A5p6wBQa6zj9rWJs/OYsOWAgkCylY+fxvHtNO/NC8A0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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