SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10631b09b4e5d6420f7fd8f31bbef72837e5cb32c8b9814487fe3c1d5598cbf8' 
  AND token = 'tNduaNSsOpXOH1WzSLsVY2c+UyVdcgGLd0hYqofu7pg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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