SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45090a3ff0525c434625df3452e9fc9a9fb3b7bbc63ebe3a509920820aee64a3' 
  AND token = 'BxqgYaxAGtBvLxStWTsOWwA1VSziZxLSbulmhiYjpcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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