SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d8b30d9324ff50b71185b2808728c3bd912b5279962021df2431f007a8fe059' 
  AND token = 'uKftCwec0cneVbYXXsV/O5ogjRfvfX3jZAzoU9vl/zQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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