SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19d0189294498e756bd0d8e23c8aa7b695744bf112ce636fd62f5a98e2cc1061' 
  AND token = 'mbS8eAo0IAEi7dXDZRvyJJA8LVjaPtWCtMAifz69ogY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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