SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '427672184edcb36e5c8f28b934041662d1b49b7f32fadb5eea4b0a6df4647526' 
  AND token = 'OqylR2C/YGrjPKcuWb2p3MbRs+V1nThEFoSCUwNJwbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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