SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eae44b05798aef0057b1dc976cb8885841d411c57234307753f464d8bbec1d71' 
  AND token = 'q0VIiasNt/RYuYXxDMG2Yu77Z3s+jM7KzkmjKJY/2Z8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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