SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91d5fb33a98f561b48755dc208430f0f67cc7a0b966df211b86595f49a2697ab' 
  AND token = 'OYogDm4luyYHcbvYTwQLBwHV82vAI9FsUh9dDIjqfbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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