SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02c998d50593181210f3240c87bf0b96a9238e733ffb1716c6065d596281ad44' 
  AND token = '0NE4wU1c8DDrumE4fcZb3d4oRJSaBqQ/j4jH0fyI80A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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