SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a08b7d6bd9eefd6e4cc42bce1832f5ea4310fea697cc30c468bf61ed3fdd08c' 
  AND token = 'rHEsoTw/jSaM6f4ZfgHaN1E8YP5IXfSWekQMIKBQ6uE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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