SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510d0c04e71fa8edbd72901003fb416f8017476435a49a982ad366bd449ad39b' 
  AND token = '6QFXQgcPLYprd4A7TvuEdJzLT38AZ32AqtqG/PSZvf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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