SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d826e41d0068d51787fd8ec2a4f1478f2578286c5a5085a49864760fe68a406' 
  AND token = 'mdW8Ng6hr798rMLKugJIv8A2hnt/QgZlug66bBZbzdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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