SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ad4f1afac466466a86a42b384f2805107dc63fce84101c65cdff25757024ef3' 
  AND token = 'FQ46pggy9npGoXlIRcdGIaMgUGD+CthgMOXHuQeefvo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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