SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b1e92aa1173578aa7fe25ee44bf19d67cde31a59864468c58911d6ee4366989' 
  AND token = 'i+vj05ubuDVgojKntUwmZszO6FQ2ZZ4epsGRYCsQuUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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