SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3eef9aecfd1f122cf247b0254b1b03be27d94b4e11795424dd25bb203d7150f6' 
  AND token = 'oasVuBysR6SGw/Yl0gufudsgdr05dsgKBww2OVDbTIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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