SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c463fa3ade31631fd2b476b1a800f078274f09c752ecf8b02217a8faac609be' 
  AND token = 'aJVm7LVQNWdGfhLhA2Rw/VxOFImpcE1ZKQDPeOjMQkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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