SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0756541ca48660b61b18776b11a6316bb1dcaf9c843f89f11cf9f61c49f09e91' 
  AND token = 'R55ki/SQO5U7hV3ksjyUS+SfQmvhIuCpEQXgdVVFbAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}