SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4685c576ed1d90aa4068022c9e98c7b0e363678834a5a62ddb704f63ab183265' 
  AND token = '2I0603QBhwjAIGpfFDd/qbsDXa2Y1BriwVVOCpvWjT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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