SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '262a53eb635d5bc869bae1a3c9aa98aa12e1512a08ca8460d990c18051f72bf3' 
  AND token = 'ML+OjNyTfRBngVYWchNhwMy9vCQbpPNd88zVeOmVQEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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