SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44d7d40c0cf2b9849c157537cf477a1bddf0c26df9f7fef463fc39048c99b443' 
  AND token = 'aPN498etMs2D4hF4ZBfNwuYPyLc7Zc40pGLg4AiwHEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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