SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c30f7b52ba765f9c1ff9195bdb48a0fff4bd279809e24b717d18c34639889c3' 
  AND token = 'oK9wImLX1yZcO4O+V3ZpX1SPqSOhfjwAd3T6RQyXmzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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