SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92f9bbd3e75d6e841c492adfbd9ec27f86acfeccd574290a292b7ba4cbb4e6fd' 
  AND token = 'MInGxq7Q/S/UTxfjAE+0Mdpu+3yUxTBWSUAQjQXOEDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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