SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd74a065cd0ea1956dd31b15d837aa45f8d83641582da63f31b3f49798d0ad7a' 
  AND token = 'rkvZnMXwvxYVEaCFZIeWaNPCqX+f7U9uKpJDAI49CCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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