SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bfb415201b8748ac880e2f6e38468faf2d363d2bc46210308a4ce87b5a2a0a8' 
  AND token = 'ad7it7pju1MDW5SxYdMJKncF9AJ4+2JKmkqBCH1XlLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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