SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c13c08c13638c404aec9da022e9862a61d8501322c5930f9fbbe3491e56ef0bb' 
  AND token = '7o6+0mn4karBJI0nIox3VVXvkaBqeXt3nBk5XLZOvMA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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