SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '439d9af5489c8c256c260e51629a636b478c85865b2c83078eb41b78d157edea' 
  AND token = 'Wb2ibCmjXYjt4LCbfwPysSX73tPdquvMZGJ4BEHldgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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