SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '530322781d5cf83801dd8bce0da7e765c3cf6ad147de2781028100a0ca9852be' 
  AND token = 'jMV3bydZuzCcGaiYrE8E0hmLdaS89I2dC5lpPNayIPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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