SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '852dc5fa62e899410e1caddf4d4de216735eea7023fb48bb118b9046ac7ceb8a' 
  AND token = 'T7EIqEJpnCZIWTQTGUWC0rUv8KDRJnXpv9wGxZi71uk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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