SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7969c135ad76e2643782bac3599f101e3147e0cddcc6ca2f82ab4451699f45b' 
  AND token = 'zK+1H1eUq1CgJUPT9COZ2N5xIvqSZ8VjCNdNboJgEcY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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