SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a58eb6f3375fc04ac831a1b92855f5ab8c355191a46c4d114878ba515c69c09f' 
  AND token = 'ya3CU5z2ySEtT3XbbzDigepnbyAXCK1zKratck2tsbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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