SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2c1d987440f80749b26de42c999f0b41e283f635e3595a3bce91bb151554680c' 
  AND token = '28mxNNl2WXxot3dE/x6UPP6uuJ5ymjV0O1GLAKsdfZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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