SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c388a87f55e58996488336c69bc793245fc1985f4f512374f65f438190a058c0' 
  AND token = 'qR1rbpiGTsxTmAbO3FfxEOO7AzOkl1Qz9AxtzpNH544=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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