SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e63509fb2d49d6077a5f937a14fae5cd7821bc58b9cec10ea01009faa915da2' 
  AND token = 'mlb4aRKPE/ZCXK3Cpx3gCbbTzylw+eSp+flkUkpcorE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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